Thuvasaurs were carnivorous predators imported to the planet Eiattu 6. The thuvasaur was not a native creature, but was transported to Eiattu specifically for sport. Due to their ability to adapt to harsh environments, they quickly killed off the local predator and moved to the top of the food chain. They were said to be a distant cousin of the dewback.
Thuvasaurs were a type of non-sentient, carnivorous reptile that were a distant cousin of the dewback. They were quadrupeds with three black clawed toes on each of their feet and a fourth claw on their heel. They were large enough for a human to ride on their back. Thuvasaurs were predominantly brown, with darker brown scales covering the upper half of their body and outer sides of their limbs, and light brown scales covering their underside including half of their thick tail and their spiked throats. Thuvasaurs had a brown eye surrounded by a semicircle of spikes on either side of their head and a single horn located at the tip of their nose above their mouth.
Thuvasaurs were at some point domesticated and tamed, but after adapting to the harsh conditions of the world Eiattu 6 they became cold-blooded predators. Unlike their cousins in the dewback family, thuvasaurs were capable of harming others and dwelt in non-dry habitats, although they still did not like deep swamps. Expert creature handlers could train fierce thuvasaurs to act as riding animals, strapping saddles to their backs and bridles in their mouths.
Thuvasaurs were imported to Eiattu 6 for sport as tame and domesticated animals, but once there they adapted to the harsh environment. In time, they destroyed all of the local predators and moved to the top of the food chain. During the Great Galactic War, thuvasaurs were used as mounts or kept decoratively in some buildings and could be purchased for 50,000 credits.
In 4 ABY, a stable master on Eiattu 6 spoke with the Rogue Squadron pilot Wes Janson about thuvasaurs. Janson later relayed the information to fellow pilots Tycho Celchu and Ibtisam while they were patrolling the wilderness of Eiattu 6 near some deep swamps. Celchu and Ibtisam were surprised that the thuvasaur and dewback were related given the differences between the two creatures. When the pilot Dllr Nep heard something in the swamps, Antilles and Celchu realized it was probably not thuvasaurs in that environment, so went to investigate and discovered Imperial forces.
The thuvasaur was first mentioned in the comic book X-Wing Rogue Squadron 14, which was written by Michael A. Stackpole and Scott Tolson and published on December 1, 1996. The species was first depicted in the massively multiplayer online roleplaying game Star Wars: The Old Republic, where they became available as part of Game Update 5.2.2 on June 13, 2017. Initially only available through bought in the Cartel Market, they were then one of the items included in the "Dread Warlord Pack" on June 27 and eventually became individually purchasable for 1,500 Cartel Coins, a premium in-game currency.